There are numerous methods of printing that have been practiced over the years in making reproductions of master copy in large quantities. Very briefly, these earlier printing methods are known as letterpress, flexographic, lithographic, silkscreen and gravure printing. All of these systems involve inking a master or a printing plate or roller, and transferring an image derived from the master to paper, either directly or by an offset process. The prior systems are quite complex and require highly skilled personnel to practice them to obtain satisfactory results.
There is a need in the printing art for simplified and economical systems involving relatively low-cost apparatus capable of operation by relatively unskilled workers and operable to give good, accurate black-and-white or color reproductions in relatively small or short runs. Using the prior techniques, a particular problem arises with two-color reproductions which require extremely accurate registry between the impressions made by the several selective and related color plates. Other systems lack versatility or flexibility in the handling of the copy, and require highly skilled persons to accomplish satisfactory results. All of the mentioned prior systems involve a considerable amount of "makeready", a term widely used throughout the world in the printing industry, the meaning of which is actually "lost time", in that unproductive machine and manpower time is exhorbitant and in all cases exaggerates the cost of the finished product.
A good example is found in line color printing. The complicated and sophisticated machinery used today requires a tremendous amount of setting-up time, even for a two-color printing job. Two different sections of a machine must be set up, one for each color. Extremely accurate adjustments have to be made between the printing plates for one color and for the other, so that the paper as it passes through the machine is in accurate registry. To add a third, fourth or several other colors thoroughly complicates the matter, and a great deal of manpower is devoted to obtaining satisfactory results.
It is an object of this invention to make color printing by the use of photosensitive material capable of producing life-like reproductions from color inter-negatives in a continuous manner and without the use of color-separation negatives or color plates. It is a further object of this invention to provide a simple apparatus whereby black-and-white reproductions can be substantially produced continuously with great accuracy and crispness in the resultant end product but without resort to any of the mentioned prior systems.
These and other advantages of this invention will become more apparent in the course of the following description in which is set forth the preferred embodiment of the photoprinting apparatus.